Help:Datatype "Record"

Record
Holds compound property values that consist of a short list of values with fixed type and order
Further information
Provided by:	Semantic MediaWiki
Since version:	1.6.0
Until version:	still in use
Datatype ID:	_rec
In this wiki:	Record
Table of Contents

The datatype record is used for property values that consist of a short list of values of other datatypes. For each property that uses this datatype, the order and type of the individual fields of the record is fixed, based on a declaration with special property "Has fields"Defines a short list of fields with a fixed type and order for datatype Record on the property page. Individual fields in a record value are separated with semicolons (;).

In earlier versions of Semantic MediaWiki, record properties have also been called many-valued properties or n-ary properties.

Declaration and usage

A record property is declared by annotating the respective property page with 2 special properties:

• [[Has type::Record]], and
• a single1 annotation of [[Has fields::<field-1>;...]] listing the record's fields separated by semicolons (;), where each field is the name of another property - you must not have any two fields refer to the same property.

Defining and using a record

• Defining a record describes how record types are to be defined
• Show examples on how to use a record
• Contains examples on how to search a record
• Discuses the alternative by using subobjects

Limitations

• You cannot set the layout of the values; they will always appear as a comma-separated list.
• Fields of records cannot be the basis for special purpose query formats such as result format "Timeline"Displays query results in interactive timelines or geography related result formats, etc.

Technical notes

A record is stored internally as subobject (given its n-ary characteristics) hereby is represented by its own entity space, yet is tightly coupled to the embedding subject. Furthermore, if a record is defined by something like [[Has fields::Has foo;Has bar]] and a query contains a condition to [[Has foo::+]] then the result set will match the "native" record representation (meaning the subobject not the formatted record).

With "native" record representation2 we refer to a subobject with an anonymous identifier identifiable by _#... as part of the entity (subject, page) name.

See also

• Help page on property chains and paths
• Help:Datatype "Reference"